Page 1 : 9. TOOLS AND METHODS OF DATA COLLECTION, , , , 288, subject, the result should be similar », , i i time the test is put ona, , (e-g- introversion), each time Sanat E eedbey bat the :, is unfortunate as it is not possible to calculate are se, s to measure reliability. :, , way:, Definitions . |, Reliability isthe degree i and.accusacy with which an_instrument-measures, a esigned to measure. ., , an instrument to create reproducible results.’ Theres..., f the measurement tools. A tool only can be con, , ‘Reliability is defined as the ability of, lar results on repeated use., , reliability is concerned with consistency of B, reliable if it measures an attribute with sim, , Measuring of Reliability, the research tools, which depend, , There are several ways to measure the reliability for, , several factors, such as the nature of instrument as well as aspects of reliability the res, wants to measure. The main aspects of the reliability considered important in qu, research include: stability, internal consistency, and equivalence. One of the followi, may be considered important to measure the reliability of a research instrument, , . Stability: The stability aspect of reliability means research instrument provide, Sults when used consecutively for times, Stability is estimated to m, that research ins ent is consistent in providing similar results with repeated admins, , , , , , , , , , , , tration., , It is also known as reliability of test-retest functor To measure test-retest relia!, the test is given twice at two different points in time. It is used to measure the cons, of a test across time. This type of reliability supposes that there will be no change =, quality or construct being assessed. Test-retest reliability is suitably best used for, that are strong over time (e.g_intelligence). Reliability will be, generally, higher when Bes, time has passed between tests., , The test-retest method is a relatively easy and straightforward approach to, reliability. It is used for questionnaire, observation checklist, observation-rating scales, an, physiologic measurement tools. However, it has one basic problem that there are mal, traits that may change with time, such as attitude, behaviour, mood knowledge, satisiac, tion, physical conditions, and so on. . :, , , , , , , , estaDu>, , , , , , Statistical Calculation (Test-retest Method), , ) by ure of * ie * ane anit } je ., , | poe a eas test-retest reliability (stability) of research instrument involve :, ie istration of a research instrument to a sam j i t “i ple of subjects on two different occa, , the tool administered at two different occasions are compared and calculate f, lowing formula of correlation coefficient (Formula 9.1). fn, coefficient reveals the magnitude and directions of relationship betwe®, , oa d by azeseat ch instrument at two separate occasions.